But Sen. Barack Obama, D-Ill., did the right thing when he released his returns, acknowledging that when you want to hold the most powerful job in the world, you forfeit much of your privacy. We hope the presumptive GOP nominee, Arizona Sen. John McCain, follows suit and releases his returns, as well as Sen. Hillary Clinton, D-N.Y.

Especially Sen. Clinton.

Hillary and Bill Clinton have become extremely wealthy since Bill left the White House in 2001, and there are big question marks about how some of the family fortune was assembled. Bill Clinton last month reportedly received $20 million for his work on a global investment fund run by Ron Burkle, a California financier and grocery store magnate. One of Burkle's partners in the fund was the ruler of Dubai - and there are reports that Clinton's decision to break with Burkle means Dubai will quit the fund. Is that because Dubai so values Clinton's insight or because its investment was a way to curry favor with a past U.S. president who is the husband of a potential future U.S. president?

The list of such eyebrow-raising dealings goes on and on. The New York Times recently detailed Bill Clinton's involvement in helping a Canadian billionaire secure a lucrative uranium-mining contract from the corrupt dictator of Kazakhstan. The billionaire then gave $31.3 million to the former president's charitable organization, The Clinton Foundation, and later pledged $100 million more.

Bill Clinton could have gone a long way toward easing suspicions about this cash avalanche if he had made the finances of his foundation and his fundraising for his presidential library more transparent. Instead, he has gone the opposite route, even reportedly keeping information from his wife's presidential campaign, which fears embarrassing disclosures.

Behind all this smoke, the Clintons' history suggests there may well be a fire. There were so many scandals during Bill Clinton's eight years as president that it is easy to forget the particulars. But think back to the fundraising scandal in his 1996 re-election campaign: The most troubling part of that mess was the strong evidence that the Chinese government had funneled millions of dollars to his campaign in a bid to win influence, and that the president and his staff had ignored many warning signs. Hillary Clinton's own fundraising scandal - last year, she returned $850,000 in donations from a mysteriously wealthy California businessman named Norman Hsu - had precise echoes of what happened in 1996.

The bottom line is that on fundraising, the Clintons have shown both poor judgment and a history of attracting an unsavory lot. Would anyone be surprised if this also applied to their personal finances?

One of Hillary Clinton's key campaign themes is that given all she has already been through, she would be better able to survive the coming Republican barrage in the general election campaign than untested, unscrutinized Barack Obama. But her refusal to turn over her family's tax returns - and her husband's refusal to explain who is bankrolling his charitable foundation and his presidential library - shows who really fears scrutiny.